JP7122842B2 - Glare suppression and ranging system and method - Google Patents

Description

[0001] This application claims the benefit of US Provisional Patent Application No. 62/476,967, filed March 27, 2017. By reference herein to this provisional patent application, its entire contents are also incorporated into this application.

[0002] Scattering media interspersed between an optical imaging system and an imaging target can produce reflections or glare, obscuring the target. Glare can significantly impair an optical imaging system's ability to detect and sense an image of a target, especially if the light reflection from the target is weak. Destructive optical interference can be used to suppress glare. Optical imaging systems that use destructive interference can also have higher sensitivity than other possible imaging techniques.

[0003] In some systems, for example, remote sensing systems, it is necessary to obtain the distance of an imaging target. However, optical imaging systems that employ destructive optical interference cannot detect the distance of the imaging target. Therefore, there is a need for techniques that facilitate both glare reduction and ranging in optical imaging systems.

[0004] In one embodiment, a method for glare reduction and ranging for an optical system having a pixel-based imaging sensor is provided. The method comprises the steps of generating a first light beam having a power spectral density, generating a reference light beam from the first light beam, and emitting the first light beam having the power spectral density. , collecting the scattered light and the reflected light reflected from the scattering medium and the target, respectively; and determining the power spectral density of the first light beam such that the first light beam is substantially coherent with the scattered light. adjusting the power spectral density of the first light beam so that the reference light beam is substantially coherent with the scattered light; pixel by pixel, to minimize the DC light power at each pixel; modifying the amplitude and phase of the reference light beam; storing the modified amplitude and phase that resulted in the substantially minimum detected DC light power for each pixel; and calculating the power spectral density of the second reference light beam. modulating the amplitude of the second reference light beam with a sinusoidal signal having a frequency; and adjusting the second delay of the reference light beam on a pixel-by-pixel basis to substantially maximize the Detecting the signal level on the pixel and determining the distance to the target.

[0005] With the understanding that the drawings merely illustrate exemplary embodiments and are therefore not to be considered limiting in scope, the accompanying drawings will be used to provide further specificity for exemplary embodiments. to and in detail.
FIG. 1 illustrates one embodiment of a vehicle system including a glare reduction and ranging system. FIG. 2 illustrates one embodiment of a glare reduction and ranging optical imaging system. FIG. 3 illustrates one embodiment of the first optical processor. FIG. 4 illustrates one embodiment of the third optical processor. FIG. 5 shows one embodiment of the second optical processor. FIG. 6 shows one embodiment of the fourth optical processor. FIG. 7 illustrates one embodiment of the fifth optical processor. FIG. 8 illustrates one embodiment of a processing system. FIG. 9 illustrates one embodiment of a glare suppression and ranging method.

[0015] By convention, the various features described are not drawn to scale, but are drawn to emphasize specific features associated with the example embodiments. Reference characters refer to similar elements throughout the figures and text.

[0016] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word "exemplary" means "serving as an example, instance or illustration." Thus, any embodiment described herein as being "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are provided as exemplary implementations to enable any person skilled in the art to make or use the invention and not to limit the scope of the invention as defined by the claims. form. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background and summary or the following detailed description.

[0017] FIG. 1 illustrates one embodiment of a vehicle 101 system that includes a glare reduction and ranging system 102. As shown in FIG. In other embodiments, vehicle 101 may be an automobile, truck, train, aircraft, helicopter, drone, ship, or any other type of vehicle. In yet other embodiments, vehicle 101 further includes at least one input/output device (I/O) 105, at least one sensor 108, time, position, and vector velocity detection system 107, and/or glare suppression. and a communication system 109 coupled to the ranging system 102 . In yet another embodiment, at least one input/output device 105 includes one or more displays and is used to display images and/or distances of targets 112, for example, to passengers of vehicle 101. .

In one embodiment, glare reduction and ranging system 102 includes a processing system 104 coupled to glare reduction and ranging optical imaging system 106 . In other embodiments, the processing system 104 is located external to the glare suppression and ranging system 102, eg, elsewhere on the vehicle. In still other embodiments, processing system 102 may be part of other systems of vehicle 101, such as a flight management system or flight management computer. In yet another embodiment, at least one input/output device 105, at least one sensor 108, and/or communication system 109 are coupled to processing system 104, regardless of their location.

[0019] Glare reduction and ranging system 102 optically images target 112 behind scattering medium 110 and detects its range. In other embodiments, target 112 can be any type of physical object, such as a vehicle, a person, an animal, or a man-made or natural structure. In still other embodiments, the scattering medium can be a gas, liquid, or solid object, such as clouds, fog, rain, or reflectors.

[0020] In one embodiment, the glare reduction and optical ranging system emits an output light beam 114B that impinges on scattering medium 110 and target 112 . A portion, or a substantial portion, of output light beam 114 B may be scattered and reflected from scattering medium 110 . A portion of the output light beam 114B, the scattered light 114S, is reflected back to the glare reduction and ranging optical imaging system 106. FIG. A portion of output light beam 114 B that reaches target 112 , reflected light 114 R, is reflected back to reduction and ranging optical imaging system 106 . The power of scattered light 114S may be so much greater than the power of reflected light 114R that normally reflected light 114R becomes undetectable. However, glare reduction and ranging optical imaging system 106 can suppress scattered light 114S so that reflected light 114R can be detected. By detecting the reflected light 114R, the target 112 can be imaged and the distance can be determined. Problems arising from optical glare are discussed in Zhou et al., "Glare Suppression by Coherence Gated Negation", Optical, Vol. 3, No. 10, October 2016, pp. 1107-1113, and Further described in the corresponding published Supplementary Material. By citation of these documents herein, their entire contents are also incorporated herein.

[0021] In one embodiment, at least one sensor 108 includes a LIDAR and/or RADAR. At least one sensor 108 is configured to measure a distance from at least one sensor 108 to scattering medium 110 and/or target 112 . That is, the processing system can estimate the time delays described below for the first and/or second variable optical delay lines by multiplying the distance by two and dividing by the speed of light. In other embodiments, the first offset distance from at least one sensor 108 and glare suppression and ranging system 102 is known and stored in processing system 104 . These distances and time delays can be estimated more accurately by compensating for this first offset vector distance. This is a technique known to those skilled in the art.

[0022] In one embodiment, communication system 109 includes one or more of HF, VHF, satellite, cellular network, Wi-Fi, Wi-Max, and/or AeroMAC communication transceivers and associated antennas. . In other embodiments, communication system 109 is coupled to processing system 109 . In still other embodiments, the three-dimensional positions and/or vector velocities of scattering media 110 and/or targets 112, e.g., their centers of mass, may be transferred to other vehicle(s), satellite(s) ), and/or by ground station(s), eg, by LIDAR and/or RADAR. The measured three-dimensional positions and/or vector velocities are then transmitted to vehicle 101 via communication system 109 . In yet another embodiment, ranging and imaging measurements of target 112 made by glare suppression and ranging system 102 may be performed by other vehicle(s), satellite(s), and /or communicated via communication system 109 to ground station(s).

[0023] In one embodiment, the time, position, and vector velocity detection system 107 includes a Global Navigation Satellite System (GNSS) receiver, eg, a GPS receiver, and/or an inertial management unit (IMU). In other embodiments, the IMU includes at least one gyroscope and/or at least one accelerometer. In still other embodiments, the GNSS receiver and IMU may be coupled together and/or coupled to the processing system 104 . The time, position and vector velocity detection system 107 monitors the current time of day, the position of the vehicle 101 and the vector velocity of the vehicle 101 . In yet another embodiment, measurements made by at least one sensor 108 and glare reduction and ranging optical imaging system 106 are time stamped to increase the accuracy of ranging and corresponding time delay calculations. The time of stamp originates from the time, position and vector velocity detection system 107 .

[0024] In one embodiment, the estimated scattering medium 110 and/or target 112 positions based on the information provided are communicated to the processing system 104 via the communication system 109 . Based on this information, processing system 104 can determine glare suppression and ranging system 102 and scattering media 110 and/or targets 112, even if both vehicle 101 and scattering media 110 and/or targets 112 are moving. can be determined or estimated (and thus the corresponding time delays) between. In other embodiments, the time, position, and position of the vector velocity detection system 107 (or the corresponding position in the vehicle determined by this system) and a second offset vector distance from the glare suppression and ranging system 102 is known and stored in processing system 104 . These distances and time delays can be estimated more accurately by considering the second offset vector distance, in a manner well known to those skilled in the art.

[0025] FIG. 2 illustrates one embodiment of a glare reduction and ranging optical imaging system 206. As shown in FIG. The glare reduction and ranging optical imaging system 206 can be implemented in other ways. For example, the glare reduction and ranging optical imaging system 206 can also be implemented using other implementations of mirrors.

[0026] The illustrated glare reduction and ranging optical imaging system 206 includes a light source 220, a first signal generator 221A, a first beam splitter (BS) 222A, a first mirror 226A, a second beam splitter 222B, a second It includes a mirror 226B, a second optical processor 224B, a third beam splitter 222C, an image sensor 228, a third mirror 226C, a fourth mirror 226D, a fourth beam splitter 222D, and a fifth beam splitter 222E. In another embodiment, the glare reduction and ranging optical imaging system 206 includes a first light processor 224A. In still other embodiments, imaging sensor 228 is a high speed photodetector with fine temporal resolution, such as an intensified charge-coupled device or a single-photon avalanche diode array. In yet another embodiment, the imaging sensor 228 has X×Y, eg, 100×100 pixels 229 . In yet another embodiment, the pixel size is smaller than the corresponding image speckle size to ensure that no phase variation occurs across the surface at any given pixel.

[0027] In one embodiment, light source 220 is a laser, eg, a current controlled distributed Bragg reflector laser, and may be a semiconductor laser. In another embodiment, light source 220 operates at a wavelength of approximately 1550 nanometers. First signal generator 221 A is coupled to light source 220 . The first signal generator 221A generates a signal, eg a current signal, having a first power spectral density in the frequency domain (corresponding to a first coherent function in the time domain) on the carrier frequency of the light source 220 . In still other embodiments, the first coherence function and the first power spectral density have a Gaussian distribution. However, the first power spectral density can be implemented to produce any coherence function. Thus, light source 220 produces source beam 214A, which is a continuous wave having a first power spectral density. In yet another embodiment, light source 220 emits a linearly (vertically or horizontally) polarized beam.

[0028] In one embodiment, the first signal generator 221A is coupled to the processing system 104; In other embodiments, processing system 104 controls the power spectral density of source beam 214A by controlling the signal generated by first signal generator 221A. In still other embodiments, the first signal generator 221A is an arbitrary waveform generator.

[0029] The following is undertaken when the source beam 214A is projected onto the target 112, eg, through the scattering medium 110. As shown in FIG. In one embodiment, the power spectral density of source beam 214A is initially the default power spectral density produced by, for example, source 220 and having a relatively narrow Gaussian distribution. Subsequently, the width of the power spectral density of source beam 214A is increased stepwise. In other embodiments, this is done by processing system 104, which directs first signal generator 221A to generate a signal correspondingly shaping the desired power spectral density of source beam 214A. Control. As the power spectral density of source beam 214A widens, the width of the corresponding coherence function narrows.

[0030] For each step, including the default power spectral density, the processing system 104 calculates the maximum and minimum gray scale values (at different pixels) detected by the imaging sensor 228, ie, the detected gray scale values. A scale dynamic range is determined and, for example, stored. In one embodiment, this gray scale ranges from zero (no incident signal, black) to one (all incident signal, white). In yet other embodiments, the processing system 104 calculates the local maxima of the dynamic range (e.g., the maximum difference between the maximum and minimum gray scale values at different pixels of the imaging sensor 228) and A corresponding power spectral density is determined and, for example, stored. The maximum gray scale dynamic range is achieved when source beam 214A is so coherent with scattered light 114S that scattered light 114S can be canceled or substantially canceled by glare suppression and ranging system 102. handle. Processing system 104 then controls first signal generator 221A to produce a signal that causes source beam 214A to produce a signal having a power spectral density corresponding to the maximum gray scale dynamic range.

[0031] The light source beam 214A is then incident on the first beam splitter 222A. In one embodiment, one or more of the beam splitters described herein are cube beam splitters or planar beam splitters. A first beam splitter 222A splits the source beam 214A into a pre-output light beam 214P and a first reference light beam 214C.

[0032] In one embodiment, the first reference light beam 214C is coupled to a first light processor 224A. In this embodiment, first optical processor 224A optically processes first reference light beam 214C to produce processed first reference light beam 214D, as exemplified below. However, if the first light processor 224 is not utilized, the first reference light beam 214C, then also referred to as the second reference light beam 214C, will be the same as the second reference light beam 214C.

[0033] In one embodiment, the load first reference light beam 214D is then incident on the first mirror 226A. First mirror 226A reflects processed first reference light beam 214D at an angle of, for example, 90 degrees. In other embodiments, processed first reference light beam 214D is then incident on second beam splitter 222B. A second beam splitter 222B couples a first portion 214D' of the processed first reference light beam to a third optical processor 224C and a second portion 214D'' of the processed first reference light beam to a second optical processor. 224 B. In yet another embodiment, a second mirror splits the processed first reference light beam 214 D so that it is combined into 224 B. In yet another embodiment, a second mirror splits the processed first reference light beam at a second angle, for example, at a 90 degree angle. It reflects the portion 214D'' and couples it to the second optical processor 224B.

[0034] The second optical processor 224B optically processes the second portion 214D'' of the processed first reference light beam to produce a second reference light beam 214E, as exemplified below. Reference light beam 214 E is incident on fourth beam splitter 222 D, which directs second reference light beam 214 E to imaging sensor 228 .

[0035] The first portion 214D' of the processed first reference light beam is coupled to a third light processor 224C. A third optical processor 224C optically processes the first portion 214D' of the processed first reference light beam to produce a third reference light beam 214F, as exemplified below. A third optical processor 224C couples a third reference light beam 214F to a third beam splitter 222C. Third beam splitter 222C directs third reference light beam 214F to fourth beam splitter 222D. A fourth beam splitter 222D directs the third reference light beam 214F to the imaging sensor 228. FIG.

[0036] In one embodiment, the output front light beam 214P is directed to a fifth light processor 224E. In other embodiments, the output front light beam 214P is reflected by a third mirror 226C, eg, by a 90 degree angle, and directed to a fifth light processor 224E. A fifth optical processor 224E optically processes output pre-light beam 214P to produce output light beam 214B, as exemplified below. A fifth optical processor 224E directs the output light beam 214B to a fifth beam splitter 222E. In yet another embodiment, the output light beam 214B is reflected by a fourth mirror 226D, eg, by a 90 degree angle, and directed to a fifth beam splitter 222E. After passing through fifth beam splitter 222E, output light beam 214B is emitted from glare reduction and ranging optical imaging system 206 toward target 112, eg, into free space.

[0037] In one embodiment, scattered light 214S and reflected light 214R are reflected back to glare reduction and ranging optical imaging system 206 from scattering medium 110 and target 112, respectively. Scattered light 214S and reflected light 214R are incident on and pass through fifth beam splitter 222E.

[0038] Scattered light 214S and reflected light 214R are coupled by a fifth beam splitter 222E to a fourth optical processor 224D. A fourth optical processor 224D optically processes scattered light 214S and reflected light 214R to produce processed scattered light 214S' and processed reflected light 214R', as exemplified below.

[0039] Processed scattered light 214S' and processed reflected light 214R' are coupled from a fourth optical processor 224D to a third beam splitter 222C. Third beam splitter 222C couples processed scattered light 214S' and processed reflected light 214R' to fourth beam splitter 222D. Fourth beam splitter 222D couples processed scattered light 214S' and processed reflected light 214R' to imaging sensor 228. As shown in FIG.

[0040] In one embodiment, the imaging sensor 228 and each pixel within it has a linear response to optical power. In other embodiments, the imaging sensor 228 and each pixel within it has a square law response to the optical field. Due to the nonlinear response, processed scattered light 214S', processed reflected light 214R', second reference light beam 214E, and third reference light beam 214F are mixed to produce a mixing product. Detection of desired mixtures and suppression of undesired mixtures enables glare reduction, target 112 imaging, and target 112 ranging. This will be explained subsequently.

[0041] Figure 3 illustrates one embodiment of the first optical processor 324A. The illustrated first optical processor includes a first linear polarizing filter (LPF) 332A. In another embodiment, the first optical processor 324A includes a first variable optical delay line 334A. First variable optical delay line 334 A is coupled to processing system 104 . In other embodiments, first optical processor 324A includes only first variable optical delay line 334A. First polarizing filter 332A and corresponding polarizing filters in fourth and fifth optical processors 224D and 224E are used to facilitate suppression of scattered light 214S, imaging of target 112, and ranging of target 112. has the same linear polarization (vertical or horizontal) as that of source beam 214A produced by 220;

[0042] The first reference light beam 214C is filtered by a first linear polarizing filter (LPF) 332A such that only the desired linear polarization continues to propagate. In one embodiment, the liner polarizers described herein are formed from polymers. The linearly polarized first reference light beam then passes through a first variable optical delay line 334A. In other embodiments, the variable optical delay lines described herein are programmable or electronically controlled electronic or electrical delay lines using optical filters, microelectromechanical systems, and/or solid state devices. It is a mechanical variable optical delay line.

[0043] In one embodiment, the delay of the first optical delay line 334A is equal to the delay in the time delay of the transmission and reflection paths of the scattered light 214S reflected from the scattering medium 110 by the processing system 104, for example. controlled, eg programmed. In other embodiments, this time delay is known or calculated from range data provided by an external data source or generated by at least one sensor 108 as described above.

[0044] Figure 4 illustrates an embodiment of a third optical processor 424C. A first portion 214D' of the first reference light beam is coupled to a third optical processor 424C. Third optical processor 424C emits third reference light beam 214F.

[0045] The illustrated third optical processor 424C includes a first optical amplitude modulator (AM) 436A coupled to a first optical phase modulator (PM) 438A. In other embodiments, first optical amplitude modulator 436 A and first optical phase modulator 438 A are coupled to and controlled by processing system 104 . In yet another embodiment, first optical amplitude modulator 436A and first optical phase modulator 438A are electronically programmable devices. In yet another embodiment, the optical amplitude modulators described herein are electronically controllable Pockel cell type modulators that include two matched lithium niobate crystals. In yet another embodiment, the optical phase modulators described herein include crystals that are electronically controllable and have an optical phase shift. The optical phase shift varies based on the level of voltage applied across the crystal.

[0046] In one embodiment, for each pixel of the imaging sensor 228, the first optical amplitude modulator 436A and the first optical phase modulator 438A provide a range of amplitude and phase values, eg, N amplitude steps and Y steps. , the amplitude and phase are permuted. Cancellation of unwanted scattered light 214S can be increased by adjusting the integers of N and Y. FIG.

[0047] The DC signal amplitude detected by each pixel is measured for each combination of amplitude and phase. Store the set of amplitude and phase values that produced the lowest DC signal amplitude detected by each pixel. This set corresponds to amplitude and phase values for each pixel and produces destructive optical interference that provides substantially maximum cancellation of the power of the unwanted scattered light 214S. To achieve this destructive optical interference, the second reference light beam 214F has substantially the same amplitude as the processed scattered light 214S' and a phase 180 degrees out of phase with the processed scattered light 214S'. 0, have. The signal with the lowest DC component represents the image signal of the target on the pixel.

[0048] Then, for each pixel, processing system 104 modulates first optical amplitude modulator 436A and first optical phase modulator 436A to enable substantially maximum cancellation of the interference of undesired scattered light 214S. The amplitude and phase settings of each 438A can be electronically controlled. As a result, imaging and ranging of the target 112 can be determined with higher accuracy.

[0049] In one embodiment, the third light processor 424C includes a first lens 442A, eg, a collimating lens. In other embodiments, the output of first optical phase modulator 438A is coupled to first lens 442A, and the output of first lens 442A is second reference light beam 214F.

[0050] Figure 5 illustrates one embodiment of a second optical processor 524B. A second portion 214D″ of the first reference light beam is coupled to a second light processor 524B. The second light processor 524B emits a second reference light beam 214E.

[0051] The illustrated second optical processor 524B includes a second variable optical delay line 534B coupled to a second optical amplitude modulator 536B. A second signal generator 512B is also coupled to the second optical amplitude modulator 536B.

[0052] In one embodiment, the second optical amplitude modulator is coupled to the second optical phase modulator 538B. A second optical phase modulator 538B is coupled to a third signal generator 521C. In other embodiments, the second variable optical delay line 534B is coupled to the processing system 104 and is controlled, eg, programmed by the processing system 104. FIG.

[0053] The second signal generator 521B generates a sine wave that amplitude modulates a second portion of the first reference light beam 214D. Although the frequency of this sine wave may be relatively low, by modulating the second portion of first reference light beam 214D, the second portion of first reference light beam 214D is substantially maximal of scattered light 214S. It does not contain a time-varying DC component that interferes with obtaining cancellation of . In one embodiment, the sine wave frequency is between 1 kHz and 1 MHz.

[0054] The third signal generator 521C generates a power spectral density that is broader than the power spectral density of the output light beam 214B, and thus the processed reflected light 214R', and thus a narrower than the coherence function of the output light beam 214B. A signal is generated to modulate the second phase modulator 538B to cause the second portion 214D″ of the first reference light beam to have a coherence function, respectively. In one embodiment, the second phase modulator 538B of the first reference light beam The power spectral density and coherence function of portion 214D″ have a Gaussian distribution. Since the coherence function of the second reference light beam 214E is decreased, the accuracy of the distance measurement of the target 112 is increased. In other embodiments, third signal generator 521 C is coupled to processing system 104 . The processing system 104 causes each of the first reference light beams 214D″ to have a power spectral density that is broader than the power spectral density of the output light beam 214B and thus a coherence function that is narrower than the coherence function of the output light beam 214B. It controls the third signal generator 521C to generate a signal that causes the third signal generator 521C to be implemented by any waveform generator.

[0055] Returning to the second variable optical delay line 534B, in one embodiment, for each pixel, the delay of the second variable optical delay line 534B is increased incrementally, eg, from zero delay. In other embodiments, the delay of the second variable optical delay line 534B is not varied from pixel to pixel.

[0056] When such a delay equals or approximates the round trip distance between the target and the scattering medium 110, e.g. The measured output, eg voltage or current level, reaches a substantially maximum value or peak at the frequency of the amplitude modulation, eg sinusoidal wave. This time delay value is used to calculate the target distance.

Therefore, the sum of the delays of first variable optical delay line 334 A and second variable optical delay line 534 B is equal to the round trip time of reflected light 214 . That is, the distance from the glare reduction and ranging optical imaging system 206 to the target is the sum of the delays of the first variable optical delay line 334A and the second variable optical delay line 534B divided by two, multiplied by the speed of light. . In one embodiment, such distances can be determined in processing system 104 .

[0058] In one embodiment, the second light processor 524B includes a second lens 524B, eg, a collimating lens. In other embodiments, the optical output of second optical phase modulator 538B is coupled to second lens 542B, and the output of second lens 542B is second reference light beam 214E.

[0059] Figure 6 illustrates an embodiment of a fourth optical processor 624D. Scattered light 214S and reflected light 214R are coupled to fourth light processor 624D. Fourth light processor 624D emits processed scattered light 214S' and processed reflected light 214R'.

[0060] The illustrated fourth optical processor 624D includes an objective lens 644 coupled to a second linear polarizing filter 632B. Objective lens 644 collects scattered light 214S and reflected light 214R. The collected scattered light 214S and reflected light 214R are then filtered by a second linear polarizing filter 632B such that only the intended linearly polarized light passes through the fourth optical processor 624D.

[0061] In one embodiment, the fourth light processor 624D includes a third lens 624C, eg, a collimating lens. In other embodiments, the light output of second linear polarizing filter 632B is coupled to third lens 642C, the output of which is processed scattered light 214S' and processed reflected light 214R'.

[0062] Figure 7 illustrates an embodiment of a fifth optical processor 724E. Output front light beam 214P is coupled to a fifth optical processor 724E. Fifth optical processor 724E emits output light beam 214B.

[0063] The illustrated fifth optical processor 724E includes a third linear polarizing filter 732C. The output pre-light beam 214P is filtered by a third linear polarizing filter 732C such that only the intended linear polarization passes through the fifth optical processor 724E.

[0064] FIG. 8 illustrates one embodiment of a processing system 804. As shown in FIG. The illustrated embodiment includes memory 801A coupled to processor 804B. In other embodiments, all or part of memory 801A coupled to processor 804B may be implemented by a state machine or field programmable gate array.

[0065] In one embodiment, the memory 801A comprises a distance determination and imaging system 804A-1 and a glare suppression system 804A-2. In other embodiments, range determination system and imaging system 804A-1 determines delay settings for first variable optical delay line 334A and second variable optical delay line 534B using the techniques described herein. and control. For example, a first time delay for first variable optical delay line 334A may be determined by measuring the range between vehicle 101 and scattering medium 110 using LIDAR and/or RADAR. can be done. The time delay for the first variable optical delay line 334A can be calculated from the measured distance as described herein. Also, for example, a second time delay for second variable optical delay line 534B may be applied until a substantial peak or maximum of the mixture of second reference light beam 214E and processed reflected light 214R' is detected. The delay can be determined, for example, by incrementing from zero. In other embodiments, range determination and imaging system 804A-1 identifies and stores such maximum or values and corresponding second delays for each pixel. Thus, range determination and imaging system 804A-1 also stores an image of target 112. FIG.

[0066] In one embodiment, glare suppression system 804A-2 increments the amplitude and phase settings of first optical amplitude modulator 436A and first optical phase modulator 436B, respectively, for each pixel 229 of imaging sensor 228. Stores the amplitude and phase settings for incremental changes. Glare suppression system 803A-2 also stores the measured DC values and corresponding amplitude and phase settings. In addition, glare suppression system 804A-2 also identifies and stores, for each pixel 229, the minimum measured DC value and corresponding amplitude and phase settings.

[0067] In one embodiment, glare suppression system 804A-2 includes an interpolation system to improve glare suppression. The interpolation system calculates the amplitude and phase settings that give the minimum DC value based on the measured DC values and the corresponding pairs of amplitude and phase settings. In another embodiment, the interpolation system uses a least-mean-square fit to calculate the minimum DC value and the corresponding pair of amplitude and phase settings.

[0068] FIG. 9 illustrates an embodiment of a glare suppression and ranging method 900. In FIG. It is understood that to the extent the embodiment of method 900 shown in FIG. 9 is described herein as being implemented in the system shown in FIGS. 1-8, other embodiments may be implemented in other ways. It should be expected. The blocks of the flow diagram are generally ordered for ease of explanation. However, it should be understood that this arrangement is merely exemplary, and the operations associated with the method (and the blocks shown in the figure) may occur in a different order (e.g., at least one of the operations associated with the blocks). some are executed in parallel and/or in an event-driven manner).

[0069] In one embodiment, at block 950, for example, from the glare reduction and ranging optical imaging system 106, a first delay substantially equal to the round trip delay to the scattering medium 110 is obtained. In other embodiments, this delay is obtained from memory 804A of processing system 804, for example. In yet another embodiment, the distance from at least one sensor 108, eg, LIDAR or RADAR, to scattering medium 110 is determined, and the first delay is determined from this measured distance. In still other embodiments, the position of the scattering medium 110 is determined and the first delay is calculated, eg, via communication system 109 from another vehicle, ground station, or satellite.

[0070] At block 952, an output light beam 114B having a power spectral density corresponding to a particular coherence function is generated. In one embodiment, the power spectral density and corresponding coherence function have a Gaussian distribution.

[0071] At block 954, a reference light beam is generated from the first light beam. At block 956 , a first light beam having a power spectral density is emitted, for example, toward scattering medium 110 and target 112 .

[0072] At block 958, scattered light 214S and reflected light 214R reflected from scattering medium 110 and target 112, respectively, are collected. At block 959, output light beam 114B, the first reference light beam, is substantially coherent with scattered light 114S, e.g., the maximum gray scale dynamic range measured by the sensor as described above. Determine the power spectral density of the output light beam 114B corresponding to . In other embodiments, the power spectral density of output light beam 114B is adjusted such that output light beam 114B, the first reference light beam, is substantially coherent with scattered light 114S.

[0073] In one embodiment, at block 960, the reference light beam is delayed by a first delay. At block 962, the amplitude of the collected scattered light 214S is respectfully substantially equal to and 180 degrees out of phase with the collected scattered light 214S (e.g., the collected scattered light 214S incident on each pixel) ), the amplitude and phase of the delayed reference light beam are varied on a pixel-by-pixel basis. This results in a substantially minimum detected DC light power, or minimum DC light power, at each pixel. In one embodiment, block 963 stores the corresponding modified amplitude and phase of the reference light beam (which in one embodiment is delayed). In another embodiment, the minimum DC optical power at each pixel is stored. In yet another embodiment, the settings for the first amplitude modulator 436A and the first phase modulator 438A are stored. In another embodiment, by interpolation (based on measurements and corresponding phase and amplitude values), the modified amplitude and phase of the delayed reference light beam that yields the minimum detected DC optical power at each pixel is calculated.

[0074] At block 966, the power spectral density of the second reference light beam, e.g., the second portion 214D" of the first reference light beam, is adjusted to be broader than the power spectral density of the output light beam 214B, i.e. , such that it has a narrower coherence function than the coherence function of output light beam 214 B. At block 968, in one embodiment, the amplitude of the delayed first reference beam is modulated with a sinusoidal signal.

[0075] At block 970, for each pixel, the second delay of the reference light beam is adjusted, for example gradually, from zero delay until a substantially maximum incident light level impinging on the pixel is detected. By increasing, a substantially maximum incident signal level at the modulation frequency of the sinusoidal signal is detected on the pixel. Before increasing the second delay for a pixel, the amplitude and phase of the reference beam are adjusted to substantially cancel the collected scattered light 214S incident on that pixel. In one embodiment, block 970 is performed for a subset of all pixels of image sensor 228 .

[0076] In one embodiment, substantially the maximum incident light level is stored for each pixel. In another embodiment, at block 974, for example, the first delay (which is zero if the first delay is not used) and the second delay are added and the resulting sum is divided by two, resulting in Calculate the range to target 112 by multiplying the resulting product by the speed of light. In still other embodiments, this distance is calculated for each pixel, or alternatively it is averaged over all the second delays measured for each pixel. In yet another embodiment, block 976 displays an image of the target 112, eg, the substantially minimum incident DC light level for each pixel, and the calculated distance.
Embodiment example
[0077] Example 1 is a method of operating a glare reduction and ranging optical imaging system having an image sensor including pixels, the method comprising the steps of generating a first light beam having a power spectral density; generating a reference light beam from the one light beam; emitting a first light beam having a power spectral density; collecting scattered light and reflected light reflected from the scattering medium and the target, respectively; determining a power spectral density of a first light beam such that one light beam is substantially coherent with the scattered light; adjusting the power spectral density of the beam; pixel by pixel, varying the amplitude and phase of the reference light beam to minimize the DC light power at each pixel; storing the modified amplitude and phase from which the DC light power is obtained; increasing the power spectral density of the second reference light beam; modulating the amplitude of the second reference light beam with a sinusoidal signal having a frequency; detecting, for each pixel, a substantially maximum signal level at the modulation frequency on the pixel by adjusting a second delay of the reference light beam; and determining the distance to the target. .

[0078] Example 2 is the method of Example 1, further comprising displaying at least one of an image of the target and the calculated distance.
[0079] Example 3 is the method of any of Examples 1-2, further comprising delaying the reference light beam by the first delay.

[0080] Example 4 is the method of any of Examples 1-3, further comprising obtaining a first delay substantially equal to the round trip delay between the scattering medium and the glare reduction and ranging optical imaging system. including.

[0081] Example 5 is the method of Example 4, wherein obtaining the first delay comprises obtaining the first delay from at least one sensor.
[0082] Example 6 is the method of any of Examples 1-5, wherein the step of storing the modified amplitude and phase that resulted in the substantially minimum detected DC light power for each pixel is determined by interpolation. storing the modified amplitude and phase.

[0083] Example 7 is a glare suppression and ranging system comprising a processing system and a glare reduction and ranging optical system coupled to the processing system, wherein the glare reduction and ranging optical system is a source light beam and a first signal generator coupled to the light source, the first signal generator configured to alter the power spectral density of the source light beam; a first beam splitter coupled to the first beam splitter, such that the first beam splitter creates an output light beam and a first reference light beam, and the output beam is emitted to produce a scattered beam and a reflected beam; and a second beam splitter optically coupled to the first reference light beam, wherein the second beam splitter forms the second reference light beam. a beam splitter; a first optical processor configured to adjust the amplitude and phase of the first reference light beam; and configured to adjust the delay and power spectral density and frequency modulate the second reference light beam. and an imaging sensor comprising pixels and configured to receive the scattered beam, the reflected beam, the adjusted first optical reference beam, and the adjusted second reference light beam.

[0084] Example 8 is the glare suppression and ranging system of Example 7, further including a third light processor configured to adjust the delay of the source light beam.
[0085] Example 9 is the glare suppression and ranging system of any of Examples 7-8, wherein the processing system further includes a memory and a processor coupled to the memory.

[0086] Example 10 is the glare suppression and ranging system of Example 9, wherein the memory includes the range determination and imaging system and the glare suppression system.
[0087] Example 11 is the glare suppression and ranging system of any of Examples 7-10, wherein the first optical modulator is a first amplitude modulator coupled to the processing system; and a first phase modulator coupled to the system.

[0088] Example 12 is the glare suppression and ranging system of any of Examples 7-11, wherein the second optical modulator is coupled to the first variable optical delay line and to the first optical delay line. a second phase modulator coupled to the second amplitude modulator; a second signal generator coupled to the second amplitude modulator; a second phase modulator and coupled to the processing system and a third signal generator.

[0089] Example 13 is the glare suppression and ranging system of any of Examples 7-12, further including an objective lens optically coupled to the imaging sensor.
[0090] Example 14 is a system including a glare suppression and ranging system, the glare suppression and ranging system including a processing system and a glare reduction and ranging optical system coupled to the processing system. The glare reduction and ranging optical system includes a light source that produces a source light beam and a first signal generator coupled to the light source, wherein the first signal generator alters a power spectral density of the source light beam. and a first beam splitter optically coupled to the source light beam, wherein the first beam splitter produces an output light beam and a first reference light beam, comprising: , a first beam splitter configured to emit an output light beam to produce a scattered beam and a reflected beam, and a second beam splitter optically coupled to the first reference light beam, wherein a second beam splitter, the second beam splitter forming a second reference light beam; a first optical processor configured to adjust the amplitude and phase of the first reference light beam; and a delay and power spectrum. a second optical processor configured to adjust the density and frequency modulate the second reference light beam; and comprising pixels, the scattered beam, the reflected beam, the adjusted first optical reference beam, and the adjusted second reference. It includes an imaging sensor configured to receive a beam of light and at least one input/output device.

[0091] Example 15 is the system of Example 14, further comprising: (a) at least one sensor coupled to the glare suppression and ranging system; (b) time coupled to the glare suppression and ranging system; position and vector velocity detection system; and (c) a communication system coupled to the glare suppression and ranging system.

[0092] Example 16 is the glare suppression and ranging system of any of Examples 14-15, further including a third optical processor configured to adjust the delay of the source light beam.
[0093] Example 17 is the glare suppression and ranging system of any of Examples 14-16, wherein the processing system further includes a memory and a processor coupled to the memory.

[0094] Example 18 is the glare suppression and ranging system of any of Examples 14-17, wherein the memory includes the range determination and imaging system and the glare suppression system.
[0095] Example 19 is the glare suppression and ranging system of any of Examples 14-18, wherein the first optical modulator is a first amplitude modulator coupled to the processing system; and a first phase modulator coupled to the system.

[0096] Example 20 is the glare suppression and ranging system of any of Examples 14-19, wherein the second optical modulator is coupled to the first variable optical delay line and to the first optical delay line. a second phase modulator coupled to the second amplitude modulator; a second signal generator coupled to the second amplitude modulator; a second phase modulator and coupled to the processing system and a third signal generator.

[0097] Although specific embodiments have been illustrated and described herein, any arrangement believed to achieve the same purpose may be used in place of the specific embodiments illustrated. It will be appreciated by those skilled in the art. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Claims (3)

A glare suppression and ranging system comprising:
a processing system ;
a glare reduction and ranging optical system coupled to the processing system ;
wherein the glare reduction and ranging optical system comprises
a light source configured to generate a source light beam ;
a first signal generator coupled to the light source ;
wherein the first signal generator is configured to alter the power spectral density of the source light beam ;
a first beam splitter optically coupled to the source light beam ;
wherein the first beam splitter is configured to form an output light beam and a first reference light beam;
the output light beam is configured to be emitted to produce a scattered beam and a reflected beam ;
a second beam splitter optically coupled to the first reference light beam;
wherein the second beam splitter is configured to form a second reference light beam;
a third optical processor configured to adjust the amplitude and phase of the first reference light beam;
a second optical processor configured to adjust the delay and power spectral density of the second reference light beam and frequency modulate the second reference light beam;
a first optical processor configured to adjust the delay of the light source light beam;
an imaging sensor comprising pixels and configured to receive the scattered beam, the reflected beam, a third optical reference beam, and a fourth optical reference beam;
glare suppression and ranging systems, including; 2. The glare suppression and ranging system of claim 1, further comprising an objective lens optically coupled to said imaging sensor . 2. The glare suppression and ranging system of claim 1, wherein the third light processor comprises:
a first amplitude modulator coupled to the processing system;
a first phase modulator coupled to the first amplitude modulator and the processing system;
including
the second optical processor ,
a first variable optical delay line;
a second amplitude modulator coupled to the first variable optical delay line;
a second phase modulator coupled to the second amplitude modulator;
a second signal generator coupled to the second amplitude modulator;
a third signal generator coupled to the second phase modulator and the processing system;
glare suppression and ranging systems, including;

Images